Radio communication system



April 27, 1926.

ANTENNA CONNECT/0N B. ROSENBAUM RADIO COMMUNICATION SYSTEM Filed Sept.2, 1921 ANTENNA foN/vfcr/o/v o HAU/0 BYDW INl/ZTOR gaa/:Mh ATTORNEYSPatented pr. 27, 1926,

UNITE LES-2,695

PPATET" FFICE.

y a MANUFACTURING COMPANY, A

CORPORATION F PENNSYLVANIA.

RADIO COMMUNICATION' SYSTEM.

Application filed September new and useful Improvements in RadioCommunication Systems (for which I have filed an application for patentin Germany, March 3, 1920, No. 80,266), of which the following is aspecification. y

Signals which are electrically transmitted without wire or along wiresor upon wires can be received by any suitablel receiving devicepossessing a more or less accurate tuning. They can therefore bereceived by unauthorized receiving stations, or if suchV unauthorizedcatching up of signals is not purported they may bring about troubles inthe operation of receiving stations intended to correspond with sendingstations having a tune approaching the tuning of the station sending outthe signals in question. Processes have already been recommendedcontemplating. the use of clocks or other devices whereby the receivingappliances of a station were released for operation at acertain definitetime of the day. Under such circumstances the station thus equippedcould not receive signals unless during a certain period of time and ata certain definite time of the day. Such arrangement has proved -inpractice very inconvenient because it is difficult to arrange matters insuoli a manner that signals are transmitted just at the appointed time.

This invention strikes out along an entirely new course and consists inan arrangement whereby receiving stations intended for a certain wavelength are released for operation for a certain definite time upon thesending out of a definite calling signal. Through this signal which actson opening keys, the station in question is enabled to^re ceive signalsduring a certain time, and after the expiration of the appointed timethe station automatically stops operating. It is however possible tosend out immediately a second call signal, which releases again foroperation the station in question for a similar period of time, etc. Bythe arrangement contemplated in this invention it becomes possible totransmit signals or news to a certain individual station at any time ofthe day and for any duration of time because as explained above thestation may' 2, 1921. Seria1 No. 498,182.

over again in succession. It is also possible to arrange matters in sucha manner that after the station has been opened it remains soindefinitely until closed by the giving out from the sending station ofa special closing signal.

If it is desired to communicate the same news to other stations, twodifferent courses may be followed in the application of this invention.The first course consists in letting out these stations for the samecall signal, namely, to cause these stations to be released foroperation or their receiving equipment to be switched in by the samesignal. Another course consists in having each station laid out for aparticular call signal, all these call stations, however, to be arranged1n such a manner as to be capableof being combined in a single callsignal, upon the sending out of which from the sending station theentire group of receiving stations considered is released for operationor switched in. Such a call signal would be made up according to aspecial call, and may consist of a series of dots or parts, in which thefirst part would constitute the own call signal of one station, thefirst part plus the second the own cali signal of another station, thelast part by itself the own call signal of a third station, etc. Thiscode signal should be merely a combination signal and should notrepresent any particular word. It should be merely made up of a sequenceof longer or shorter impulses allowing of bringing forth thecorresponding releasing action in the station intended to be influenced.

The invention may be applied not only in wireless systems but also insystems making use of wires. In ordinary telegraphy the invention wouldbring about the result that the signals transmitted are not received byall the individualapparatus connected with the line but only by suchapparatuses for which the news is intended. This invention may findapplication in practice for the transmission of weather reports, stockeX- change news items, press news, etc. It may be used in particular forthe transmission of news to subscribers. Wherever two stations areconnected in such a manner that payment is made not on the basis of thenumber of words transmitted from one station to the other, but on thebasis of the time during which transmission is effected, it becomespossibile by the simplest arrangements to arrange matters in such amanner that the transmission of news may be continued during such lengthof time as may be desired by simply causing the appointed time intervalto be repeated over and over again. For instance one may arrange fortime units of 5 minutes, in which case the transmission of news would bepaid for on a 5 minute time basis. By adopting the arrangementcontemplated in this invention, it would become possible to transmitnews at any time of the day and during any length of time, and notmerely during a 5 minute period, as the invention affords the means ofseveral individual time units being added together.

The advantages offered by this invention are self-evident. It ispractically'very difiicult upon the number of the receiving stations increasing to operate with different wave lengths to avoid the news beingreceived by unauthorized stations without bringing about disturbances inall the receiving stations. By this invention whereby the receivingstations are switched in by a special call signal sent out by thesending station, either for a definite period of time or until theclosing signal is sent out by such sending station, an absolute securityis obtained that signals of a certain wave length are not received by anunauthorized station without the knowledge of the sending station. Byhaving the apparatus sealed or locked, one may guard against a violationof the arrangement and against the adjustment of the wave length withoutthe calling signal having been sent out by the sending station.According to this invention the call signal brings into play a relaywhich connects the member intended for receiving the incoming signalwith the receiver, and connects a telephone or a recording appliance ofany kin whatsover with the receiver. The relay may however bring aboutalso a c hange in the tuning of the receiving statlon in so far as thecall signal is sent out with a wave len h different from the wave lengthof the o owing signals intended to convey the news to be transmitted,the signals arriving with a different wave length bringing about achange in the tuning of the receiving station. At the same time therelay may bring into play an alarm device, warning the operator, if any,to keep himself in readiness for the beginning of the news transmissioneither by going to the telephone or by makin sucharrangements as arenecessary for t e receiving of the news. The closing signal may consistin a di'erent arrangement of signs which, as in the first case, bringsinto play a relay existing in the receiving station, which relayswitches out and locks the receiving members or otherwise displaces thereceiving equipment, or in any other manner brings about that furthersignals of the wave length in question can no longer be received. Itwould be theoretically possible to use the same signal as calling andclosing signal and to make use of a two-way switch. However, in such anarrangement there is always the danger that upon the calling relayfailing to operate, wrong adjustments are made. The relay, reacting uponthe call signal or upon the closing signal may also be arranged in sucha manner as to switch in any amplifying device, for instance, thecurrent of a glowing cathode tube, there being thereby obtain-ed thesetting in readiness of the station and furthermore the giving out of anoptical signal in the form of glowing electrodes. The relay may likewisebring into play a time recording device operating mechanically orelectrically, which device brings about when .the time agreed upon isover, the switching out, the disconnecting and the locking of thereceiving apparatus, and at the same time sets in readiness the relayfor the receiving of a further call signal which may arrive immediatelyafter the closing of the first period if it is desired to continue theconversation, or after any period of time whatsoever. By means of a callsignal, agreed upon, there will also be released for operation a sendingstation in such a manner as to cause this sending station to announce tothe calling station that the desired call has been received or that acommunication between the two stations is going to be started.

In order to illustrate the method provided by this invention,representative receiving systems have been illustrated in theaccompanying drawings and discussed in the fol lowing description ofthose drawings. In the drawings,

Fi l is a diagrammatic representation ot a ra io receiving system inwhich a calling signal is adapted to operate a switch for connecting thereceiver to the antenna;

Fig. 2 is a diagrammatic showin of a modification of the system shown inig. l.

Referring now to Fig. 1, a radio receiver of any desired type isrepresented by the rectangle 1 the receiver referably being tuned to aXed wave lengt This receiver will be referred to for convenience as theprimary receiver. The input of this receiver ma be permanently connectedto an antenna and the output to a selector mechanism of any of thewell-known types, for example the selector shown in U. S. Letters PatentNo. 1,131,673, granted to G. Brown. This selector mechanism, which isrepresented by the rectan le 2, is adapted to close a circuit throughalocal source of energy 8 and a solenoid 4 to throw the switch 5 fromthe open tothe closed position. One set of terminals of the switch 5 maybe permanently connect` llO ved to an antenna, and the other set oftermiiials to a receiver of any desired type.

The receiver is represented by rectangle 6,'

and will be referred to for convenience as thc secondary receiver.

This system operates as previously outlined. In its operative positionthe antenna is disconnected from the receiver 6, but is connected to thereceiver 1. The calling signal is received by the receiver l andoperates the selector mechanism represented at 2 to actuate the switch 5through its solenoid Il. This connects the receiver 6 with the antenna,and it is desirable that the signals received by the receiver 6 betransmitted at a wave length different from the wave length of thecalling signal.

In Fig. 2 there is illustrated a modification of the system justdescribed, in which a relay 9 is interposed between the primary receiverdenoted by 8 and the selector mechanism 11. This selector mechanism maybe of any of the usual types, the one illustrated being the same asthatshown in U. S. Letters Patent No. 1,131,673, granted to G. Brown. Theselector mechanism is provided with two contacts 12 and 13, the first ofwhich cooperates with the arm 19 to close the circuit through solenoid15, thus closing the antenna switch 14, and the second of which fcooperates with the contact 19 to close the en sequence are sent out by.a sending station and received by the antenna 7, the receiver 8rectifies them and thus operates relay 9\in accordance with the sequenceof the transmitted signals. This relay 9 closes contacts through theelectromagnets of the selector mechanism 11, and causes'this selector tomove the contact arm 19 to the desired position. The structure andoperation of this mechanism is already` well known, and will not befurther explained here. However, when impulses of a certain sequence actupon this' selector, the contact arm 19 may be moved around so as toengage with the contact 12 and thus operate the solenoid 15 andv connectthe antenna 7 to the secondary receiver 17. The messages transmitted bythe `sending station will then be received by the receiver 17. Upon theconclusion of the transmitting of the message another signal maybe sentout by the transmitting station, which operates the selector mechanismas previously outlined and moves the contact arm 19 to engage withcontact 13, thus closing-a circuit through the solenoid 16 and op'-erating the antenna switch 14 to disconnect the secondary receiver 17Vfrom the antenna 7.

I claim:

InA a radio communication system, the method of remotely and selectivelycontrolling a plurality of receiving stations which comprisestransmitting a different series of signals of predetermined sequence foreach of said receiving stations to be controlled, receiving said signalsat each of said receiving stations, impressing said received signals ona selector operative only by means of one sequence of signals, andoperating said selector to operatively connect a `radio receiving set.

In testimony whereof I aflix my signature.

' BRUNO ROSENBAUM.'

